1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
24 */
25 /*
26 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
27 * Use is subject to license terms.
28 */
29
30 /* __rem_pio2l(x,y)
31 *
32 * return the remainder of x rem pi/2 in y[0]+y[1]
33 * by calling __rem_pio2m
34 */
35
36 #include "libm.h"
37 #include "longdouble.h"
38
39 extern const int _TBL_ipio2l_inf[];
40
41 static const long double
42 two24l = 16777216.0L,
43 pio4 = 0.7853981633974483096156608458198757210495L;
44
45 int
__rem_pio2l(long double x,long double * y)46 __rem_pio2l(long double x, long double *y)
47 {
48 long double z, w;
49 double t[3], v[5];
50 int e0, i, nx, n, sign;
51
52 sign = signbitl(x);
53 z = fabsl(x);
54 if (z <= pio4) {
55 y[0] = x;
56 y[1] = 0;
57 return (0);
58 }
59 e0 = ilogbl(z) - 23;
60 z = scalbnl(z, -e0);
61 for (i = 0; i < 3; i++) {
62 t[i] = (double)((int)(z));
63 z = (z - (long double)t[i]) * two24l;
64 }
65 nx = 3;
66 while (t[nx-1] == 0.0)
67 nx--; /* omit trailing zeros */
68 n = __rem_pio2m(t, v, e0, nx, 2, _TBL_ipio2l_inf);
69 z = (long double)v[1];
70 w = (long double)v[0];
71 y[0] = z + w;
72 y[1] = z - (y[0] - w);
73 if (sign == 1) {
74 y[0] = -y[0];
75 y[1] = -y[1];
76 return (-n);
77 }
78 return (n);
79 }
80